Assessing the Impact of Climate Change on Agricultural Water Management in Mainland Southeast Asia

This study aims to address an assessment of climate change's impact on agricultural water management in mainland Southeast Asia (MSEA). We used several agroclimatic indices, such as consecutive dry days (CDDs), maximum number of consecutive wet days (CWDs), consecutive summer days (CSUs), cold spell duration index (CDSIs), and warm and wet days (WWs), based on the Geophysical Fluid Dynamics Laboratory Earth System Model to characterize the effect of climate on crop water need (CWN) in MSEA. The climate model shows monthly precipitation and temperature patterns with acceptable accuracy but with an underestimation of precipitation and a warm bias in temperature. CDDs show a significant increase in aridity and drought occurrences, particularly in northern Myanmar, Laos, Vietnam, and northern Thailand, across different representative concentration pathways. CSUs have been seen to have a substantial influence on the region's agricultural economy. The CDSIs, on the other hand, show a decrease in the duration of cold spells, indicating the existence of milder climatic conditions that could potentially affect crop growth. The CWDs show a decreasing trend in most of the multiple regions in Thailand, Laos, Vietnam, Cambodia, and Malaysia. Though the WW index shows more wet days, this does not immediately imply improved crop growth; rather, it highlights possible changes in water availability that could affect agricultural practices. While negative CWNs in the dry season months like March and November suggest possible water shortages, which pose risks to agriculture and food security in Myanmar, northern and eastern Thailand, and Cambodia, especially at the end of the century, increases in CWNs during the rainy season correspond with anticipated higher water demands for agriculture.